Hybrid banknote with electronic indicia using near-field-communications

ABSTRACT

A hybrid high-security document includes a document and one or more independent light-emitting modules disposed on or embedded in the document. Each module comprises an antenna with multiple turns, an electronic circuit, and a light emitter mounted and electrically connected on a substrate separate from the document. The electronic circuit is responsive to electrical power provided from the antenna to control the light emitter to emit light. The electronic circuit can include a memory storing information relevant to the hybrid high-security document or its use. The information can be accessed by external readers providing electromagnetic energy to the hybrid high-security document. The hybrid high-security document can be a hybrid banknote.

PRIORITY APPLICATION

This application is a continuation of U.S. patent application Ser. No. 15/157,838, filed Jun. 18, 2016, titled “Hybrid Banknote with Electronic Indicia Using Near-Field-Communications”, which claims priority to and the benefit of U.S. Provisional Patent Application No. 62/324,578, filed Apr. 19, 2016, titled “Hybrid Banknote with Electronic Indicia using Near-Field-Communications,” the contents of which are incorporated by reference herein in their entirety.

FIELD OF THE INVENTION

The present invention relates to high-security documents such as currency and particularly to banknotes having electronically controlled inorganic light-emitting diodes embedded in the banknotes operated using near-field communications.

BACKGROUND OF THE INVENTION

Monetary instruments issued by governments such as money or currency are used throughout the world today. Government-issued currency typically includes banknotes (also known as paper currency or bills) having visible markings printed on high-quality paper, plastic, or paper impregnated with other materials, such as plastic. The visible markings indicate the denomination (value) of the banknote and include a serial number, decorations such as images, and anti-counterfeiting structures such as special threads, ribbons, and holograms. Currency circulates within an economic system as a medium of monetary exchange having a fixed value until it is physically worn out. Worn out banknotes are generally returned by banks or other financial institutions and then replaced.

Other privately issued monetary instruments, such as credit cards and gift cards, are also used by the public. These cards typically include an electronically accessible value (e.g., stored in a magnetic stripe or in a chip in the card) or an electronically accessible account that can be used to make purchases. However, the electronically stored value of the card is not readily viewed by a user.

In the past, banknotes have not been electronically enabled. However, more recently there have been proposals to use RFID (radio-frequency identification device) in banknotes to validate the banknote and avoid counterfeiting. For example, U.S. Pat. No. 8,391,688 and U.S. Pat. No. 8,791,822 disclose systems for currency validation. U.S. Pat. No. 5,394,969 describes a capacitance-based verification device for a security thread embedded within currency paper to defeat counterfeiting. Security systems for scanning a paper banknote and checking identification information in the banknote (e.g., the serial number) with a network-accessible database have been proposed, for example in U.S. Pat. No. 6,131,718.

Near-field-communications (NFC) systems also provide an electronic response to electromagnetic stimulation for enabling financial transactions by employing a set of electromagnetic communication protocols that enable two electronic devices, one of which is usually a portable device such as a smartphone, to communicate by bringing them within 4 cm of each other. These devices use electromagnetic induction between two loop antennae to communicate and transmit power, for example as disclosed in U.S. Pat. No. 7,688,270. Thus, at least one of the devices can operate without a stored energy device such as a battery. In all of these systems, however, there is no way to visibly and electronically test attributes of a banknote.

There remains a need, therefore, for currency with visible indicia that is electronically accessible.

SUMMARY OF THE INVENTION

The present invention provides a hybrid high-security document having one or more light-emitting modules disposed on or embedded in a document with or without visible markings. The document can be a conventional printed document such as a label, a commercial document such as a certificate, a stock certificate, a bond, or a bearer bond or a government-issued document such as a passport, a monetary instrument, or a license and can include additional anti-counterfeiting features such as are found in high-security documents. In an embodiment, and as described herein, a banknote is a high-security document. Other high-security documents include passports and identification cards such as driver's licenses or other government-issued identification.

Each light-emitting module comprises an antenna with multiple turns, an electronic circuit, and a light emitter mounted and electrically connected on a substrate separate and independent from the document except insofar as the one is affixed to the other. The electronic circuit is responsive to electrical power provided from the antenna to control the light emitter to emit light. In an embodiment, the electronic circuit and LED are powered solely by the energy received from the antenna. The electronic circuit can include a memory storing information relevant to the hybrid high-security document or its use. The information can be accessed by external readers providing electromagnetic energy to the hybrid high-security document.

In another embodiment, a multi-element light-emitting system comprises a plurality of independent light-emitting modules. Each independent light-emitting module includes an antenna with multiple turns, an electronic circuit, and a light emitter mounted and electrically connected on a separate substrate. The independent light-emitting modules are disposed in a pattern to form a visible indicator.

In an embodiment, a hybrid banknote mat includes a mat circuit and an antenna. The mat circuit provides a continuous or pulsed NFC signal having a pulse rate of ten, twenty, fifty, or one hundred pulses per second or greater.

A method of making a hybrid high-security document includes providing a document having visible markings, providing a source having a plurality of printable light-emitting modules, and printing one or more of the light-emitting modules onto the document or onto a flexible substrate, ribbon, film, or thread subsequently incorporated in, laminated to, or woven into the document.

A method of using a hybrid banknote comprises providing a hybrid high-security document, exposing the hybrid high-security document to an electromagnetic field so that the antenna provides power to the electronic circuit and causes the light emitter to emit light, and observing the light or detecting the light with a light detector.

In an embodiment, the electronic circuit stores information, and the method further comprises providing the electromagnetic field, reading the information, and displaying the information on a display or transferring the information to a computer system.

The electronic circuit can include a memory, for example a read-only memory or a write-once memory storing one or more values. Multiple values can be stored in a sequential order corresponding to a temporally sequential set of values and can monotonically decline in magnitude. Values stored in the hybrid high-security document can be electronically read by a teller machine having a reader and the value of the high-security document displayed on the teller machine. In a further embodiment, the teller machine can write a value to the high-security document using a writer. In an embodiment, the electronic circuit controls the written value so that it must be equal to or smaller than a value already stored in the high-security document.

A user can insert a received hybrid high-security document into a teller machine, input an input value to the teller machine, and the teller machine can write a value derived from the input value into the hybrid high-security document. The input value can represent the value of a monetary transaction, for example a purchase of goods or payment of debt and the difference between the input value and the current value can be written into the hybrid high-security document.

The present invention provides an anonymous, government-issued currency with anti-counterfeiting light emitters whose value or indicia can be visibly ascertained and can be modified electronically.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other objects, aspects, features, and advantages of the present disclosure will become more apparent and better understood by referring to the following description taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a plan view of the front and back sides of a hybrid banknote in an embodiment of the present invention;

FIG. 2 is a schematic diagram according to an embodiment of the present invention;

FIG. 3 is a schematic illustration of a light emitter with a fractured tether according to an embodiment of the present invention;

FIG. 4 is a plan view of the front and back sides of another embodiment of the present invention;

FIG. 5 is a schematic illustration of operating an embodiment of the present invention;

FIGS. 6-7 are flow charts illustrating methods of the present invention;

FIG. 8 is a schematic diagram illustrating a method of making an embodiment of the present invention;

FIGS. 9A and 9B are schematic illustrations of antennae according to embodiments of the present invention;

FIG. 10 is a schematic diagram illustrating a circuit according to an embodiment of the present invention;

FIG. 11A is a perspective according to an embodiment of the present invention and FIG. 11B is a corresponding, less-detailed and more accurate perspective at a larger scale;

FIG. 12 is a cross section of an embodiment of the present invention;

FIG. 13 is a flow graph illustrating a method of the present invention;

FIG. 14 is a table showing design alternatives according to corresponding embodiments of the present invention;

FIG. 15 is a perspective according to an embodiment of the present invention;

FIG. 16 is a timing diagram according to an embodiment of the present invention;

FIGS. 17 and 18 are flow charts illustrating methods of the present invention;

FIG. 19 is a flow chart illustrating a method of the present invention; and

FIGS. 20 and 21 are cross sections illustrating arrangements of the antenna and integrated circuits of the present invention.

The features and advantages of the present disclosure will become more apparent from the detailed description set forth below when taken in conjunction with the drawings, in which like reference characters identify corresponding elements throughout. In the drawings, like reference numbers generally indicate identical, functionally similar, and/or structurally similar elements. The figures are not drawn to scale since the variation in size of various elements in the Figures is too great to permit depiction to scale.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIG. 1, in an embodiment of the present invention a hybrid high-security document 10 includes a document 20 and one or more independent light-emitting modules 60. The document 20 can be a conventional printed document such as a label, a commercial document such as a certificate, a stock certificate, a bond, or a bearer bond or a government-issued document such as a passport, a monetary instrument, or a license and can include additional anti-counterfeiting features such as are found in high-security documents. A high-security document is a document that includes a security feature and the document 20 can be a high-security document. In an embodiment, and as described herein, a banknote 20 is a high-security document. Other high-security documents 20 include passports and identification cards such as driver's licenses or other government-issued identification. As used herein, the term “banknote” is used synonymously with high-security document and any reference to “banknote” can also be a reference to a high-security document. The banknote 20 can be a government-issued banknote 20 and can include visible markings 22 such as value indicators, decorative elements, and anti-counterfeiting structures or markings.

The light-emitting modules 60 are disposed on or embedded in the banknote 20, for example disposed on or embedded in the material on which the visible markings 22 are printed or disposed on or embedded in other elements of the banknote 20, such as a thread, ribbon, film, decal, or flexible substrate. Each light-emitting module 60 comprises an antenna 50 with multiple turns, an electronic circuit 40, and a light emitter 30 mounted and electrically connected on a substrate 62 separate and independent from the document except insofar as the one is affixed to the other. Referring also to FIG. 2, each light-emitting module 60 includes an antenna 50, for example a near-field communication (NFC) antenna or an RFID antenna that provides electrical power to the electronic circuit 40 in response to received electromagnetic radiation so that the electronic circuit 40 is responsive to electrical power provided from the antenna 50 to control the light emitter 30 to emit light. In an embodiment, the electronic circuit 40 and light emitter 30 are powered solely by the energy received from the antenna 50 and the electronic circuit 40 or hybrid high-security document 10 does not include any devices for storing energy between uses, such as a battery.

The electronic circuit 40 can include a memory 44 for storing information. The electronic circuit 40 is connected to a light emitter 30 and includes circuitry for controlling the light emitter 30 to emit light when electrical power is provided from the antenna 50. The light-emitting module 60 can include a power converter that converts a signal with a relatively high current and low voltage to a signal with a relatively high voltage and low current. The light-emitting module 60 can also or alternatively include an acoustic wave filter 52 for converting the impedance of the electrical power provided from the antenna 50 in response to received electromagnetic radiation. The acoustic wave filter 52 can be the power converter. The electronic circuit 40, light emitter 30, and optional acoustic wave filter 52 can be mounted or otherwise disposed on a substrate 62, for example by micro-transfer printing. The antenna 50 can be formed on or in or disposed on the substrate 62. Electrical wires 64 can also be formed at least partly on or in the substrate 62 to electrically connect the antenna 50, optional acoustic wave filter 52, electronic circuit 40 and light emitter 30.

The electronic circuit 40 (and optional memory 44) can be, or is a part of, or can include an integrated circuit and, in an embodiment, can be or include a small micro-transfer printable integrated circuit such as a chiplet, or a semiconductor for example having an area less than 100,000, 50,000, 20,000, 10,000, 5,000, 1,000, 500, 250, or 100 square microns. In a further embodiment, the light-emitting module 60 can be a small micro-transfer printable module, for example formed on a semiconductor or other substrate such as glass or plastic having an area less than 100,000, 50,000, 20,000, 10,000, 5,000, 1,000, 500, 250, or 100 square microns. The acoustic wave filter 52 can be a surface acoustic wave filter (SAW) or bulk acoustic wave filter (BAW), for example including AlN, and the light emitter 30 can be an inorganic light-emitting diode (iLED) 32, for example made with a compound semiconductor such as GaN or AlGaN.

Micro-transfer printable iLED 32 devices (or other devices e.g., chiplets, integrated circuits, or acoustic wave filters 52) can be formed in or on a source wafer 36 over a sacrificial portion of a sacrificial layer that, when etched, forms a tether 34 (FIG. 3) connecting the micro-transfer printable device to an anchor portion of the wafer. When transferred by a printing stamp from the wafer to a destination substrate, such as the substrate 62, the tether 34 is fractured so that a micro-transfer printed device has a fractured tether 34, as illustrated in FIG. 3. FIG. 3 is a simple illustration of an iLED 32 with a fractured tether 34 over a sacrificial portion of a source wafer.

The substrate 62 of the light-emitting module 60 can be at least one of glass, plastic, polymer, resin, silicon, a semiconductor, and a compound semiconductor, or other suitable substrates. Any one or all of the optional acoustic wave filter 52, light emitter 30, and electronic circuit 40 can be assembled on the substrate 62 using micro-transfer printing and electrically interconnected with electrically conductive wires 64 using photolithographic methods and materials to form the light-emitting module 60. The light-emitting module 60, with its various components including the substrate 62, can, in turn be micro-transfer printed or otherwise printed, transferred, or assembled onto another substrate such as the banknote 20 to form the hybrid banknote 10 or on to an intermediate substrate such as a tape or reel for high-speed printing onto a sheet or web, such as a sheet or web of banknotes 20 or flexible substrates incorporated into banknotes 20. Referring to FIG. 4, in an embodiment of the invention, the banknote 20 includes a flexible substrate, ribbon, film, or thread (all of which are indicated as ribbon 70 herein) incorporated in, laminated to, woven into, or hot-press mounted onto the banknote 20. The one or more independent light-emitting modules 60 are mounted on, embedded in, or micro-transfer printed onto the flexible substrate, ribbon 70, film, or thread. The flexible substrate, ribbon 70, film, or thread can include paper, plastic, impregnated paper, or metal foil and can be electrically insulating.

In another embodiment of the present invention, the hybrid banknote 10 includes a plurality of light-emitting modules 60 and there is no electrical interconnection between the various light-emitting modules 60 so that each light-emitting module 60 is electrically separate, independent, and disconnected. Each light-emitting module 60 is electrically independent of all of the other light-emitting modules 60 and, other than, in one embodiment, having a common substrate 62 or being mounted on a common ribbon 70 or banknote 20, can also be spatially separated and physically independent and separated, although the light-emitting modules 60 can be arranged in a desired pattern. The light-emitting modules 60 can each have a separate substrate 62 (FIG. 12) different from the banknote 20. The light-emitting modules 60 can be disposed to form at least one of a character, a graphic indicator, an icon, a number, a letter, and a pictogram or indicates a value, a date, or a person. The graphic indicator can have semantic content, for example indicating a value, a date, or a person. For example, in FIG. 4, the light-emitting modules 60 form a line. The banknote 20 can be a government-issued banknote 20 or other high-security document having visible markings 22 and the one or more light-emitting modules 60 can be disposed in a location corresponding to a portion of the visible markings 22 to highlight or otherwise indicate the portion of the visible markings 22. For example, the light emitter 30 can underline or surround a graphic element of the visible markings 22. As shown in FIG. 1, the light-emitting modules 60 form the number 500, which matches the visible marking 22 printed on the banknote 20.

Referring to FIG. 5, in an example embodiment, the banknote is a banknote 20 having a denomination (e.g., five) and the light-emitting modules 60 are disposed to form the numeral 5 on the ribbon 70 laminated onto or woven into the banknote 20 making the hybrid banknote 10. When the hybrid banknote 10 is placed near a near-field-communication field, for example a near-field-communication field generated by a smartphone or other NFC device, the antenna 50 of each light-emitting module 60 will generate electrical power, optionally voltage amplified and filtered by the acoustic wave filter 52 (FIG. 2), to the electronic circuit 40 to cause the light emitter 30 to emit light. Because the signal harvested from the antenna 50 is relatively small, it is helpful to have as long an antenna 50 extending with as many turns as possible in the light-emitting module 60 to provide enough power to light the light emitters 30. Because the light-emitting module 62 can be small and the antenna 50 needs to have a length matched to the frequency of the received signals, it can be necessary to have a large number of antenna turns. In an embodiment, the necessary number of turns are provided in a single layer; in another embodiment, multiple layers of antenna turns are provided. The signal received typically has a relatively smaller voltage and larger current. Thus, in an embodiment, the acoustic wave filter 52 is also a power converter 52 that converts the received signal to a signal with a relatively larger voltage and smaller current more suitable for providing power to the electronic circuit 40 and for lighting the light emitter 30. In a further embodiment of the present invention, the acoustic waver filter 52 is smaller than conventional acoustic waver filters, for example having an area less than 100, 50, 20, or 10 square microns suitable for micro-transfer printing and unsuitable for conventional transfer or printing methods and having a reduced number of acoustic resonant filter modes, for example a single dominant resonant mode. Although the light-emitting modules 60 are electrically separate and independent, the NFC field will provide power to all of the light-emitting modules 60 at about the same time so that the light emitters 30 will emit light visibly simultaneously, in this case forming a visible numeral 5.

Referring to FIG. 6, in an embodiment of the present invention, a banknote 20 is provided in step 100, for example using conventional currency materials and printing technologies, and a light-emitting module source wafer (e.g., source wafer 36, FIG. 3) is provided in step 110, for example using photolithographic materials and techniques. Alternatively, the light-emitting modules 60 are provided in surface-mount accessible form, or on a tape or film. The light-emitting modules 60 are printed from the light-emitting module source wafer 36 or other source to the banknote 20 in step 120 to form the hybrid banknote 10. Alternatively, referring to both FIG. 7 and FIG. 8, a banknote 20 is provided in step 100, for example using conventional currency materials and printing technologies, and a light-emitting module source is provided in step 110. A ribbon 70 is provided in step 130 and the light-emitting modules 60 are printed or otherwise disposed onto the ribbon 70 in step 140, for example by micro-transfer printing, by surface mount techniques, or from a tape and reel. The ribbon 70, with the light-emitting modules 60, is then integrated into the banknote 20 in step 150 to form the hybrid banknote 10 for example by lamination or hot-pressing. This process has the advantage of more-readily controlling the substrate (ribbon 70) on which the light-emitting modules 60 are micro-transfer printed and using conventional methods for integrating the ribbon 70 into the banknote 20.

In an embodiment, the one or more light-emitting modules 60 include different inorganic light-emitting diodes 32 that emit different colors of light, for example red, green, and blue light. The different light-emitting modules 60 can be disposed in groups for a desired effect, for example each numeral or graphic element in the disposed arrangement of light-emitting modules 60 can have a different color. In an embodiment, the electronic circuit 40 controls the light emitters in a light-emitting module 60 to flash once or to flash sequentially.

FIG. 9A illustrates a receiving antenna 50 with multiple turns (windings, or coils) on the substrate 62 for a light-emitting module 60. FIG. 9B shows a typical NFC reader antenna 50 found in a smart cellular telephone or other NFC device. FIG. 9B illustrates the approximate size of the light-emitting module 60 relative to the size of the NFC reader antenna (FIG. 9A). As is apparent from the illustration, the physical size of the light-emitting module 60 is very small relative to the NFC reader antenna.

FIG. 10 is a schematic illustrating in more detail the electronic circuit 40. The antenna 50 is electrically connected to the input of the acoustic wave filter 52 which filters and impedance converts the electrical signal from the antenna 50. The antenna 50 converts an externally generated NFC magnetic field into electrical power and the acoustic wave filter 52 is tuned to the desired electrical signal from the antenna 50 and multiplies the received electrical signal to a voltage sufficient to operate the electronic circuit 40. The output of the acoustic wave filter 52 is electrically connected to the electronic circuit 40, in this case including a rectifier and voltage multiplier that provides electrical current and a sufficient voltage through a current limiter to cause the inorganic light-emitting diode 32 to emit light. For example, the electronic circuit 40 can rectify a 13.56 MHz radio frequency signal into DC voltage, increases the voltage further, for example with a voltage doubling circuit, and regulates the current to the iLED 32. The electronic circuit 40 can be a small integrated circuit such as a chiplet or, as shown, an application specific integrated circuit 66.

The acoustic wave filter 52 is operated at a dimension of one-half wavelength and is used to implement an impedance transformer similar to that using ordinary electrical transmission lines. The acoustic wave filter 52 can operate at much smaller dimensions than electrical transmission lines utilizing only metallic conductors and typical dielectric mediums. The acoustic velocity of the acoustic wave filter 52 is only on the order of 3000 to 6000 meters per second and can therefore implement a half-wave transmission line in a distance of 0.5 mm or less for a given NFC frequency such as 13.56 MHz with a quality factor (Q) on the order of 1000 or more. The half-wave element may be acoustically grounded at two ends and driven near one end by the very low impedance antenna 50. A high impedance output is available at the center of the acoustic wave filter 52. The output voltage of antenna 50 is on the order of a few millivolts which is insufficient to power the electronic circuit 40. The acoustic wave filter 52 converts the low antenna 50 voltage via the half-wave transmission line and its associated high Q to a much higher output voltage of 0.5 volt or greater which is sufficient to energize the electronic circuit 40.

FIGS. 11A and 11B are perspectives illustrating the antenna 50, electronic circuit 40, acoustic wave filter 52 and light emitter 30 disposed on the substrate 62 to make up the light-emitting module 60. For example, the light-emitting module 60 structure of FIGS. 11A and 11B can have a length and a width less than 0.5 mm and a height less than 25 microns. Because the light-emitting module 60 structure is relatively small and does not require any external electrical connections, it is very robust under mechanical stress, for example when folded, spindled, or crumpled. The banknote 20 tends to be more flexible than the light-emitting module 60 (although the elements and substrate 62 of the light-emitting module 60 can be somewhat flexible) and will preferentially flex, reducing the stress on the light-emitting modules 60.

FIG. 12 illustrates an embodiment of the present invention in cross section. As shown in FIG. 12, the light-emitting module 60 is disposed on a ribbon 70 that is laminated to the banknote 20 (not shown) with the light-emitting module 60 between the ribbon 70 and the banknote 20. The iLED 32 emits light through the ribbon 70 so the ribbon 70 must be at least partially transparent to the frequency of emitted light, for example 50%, 60%, 70%, 80%, 90%, or 95% transparent. This construction protects the light-emitting module 60 from environmental or mechanical damage. Such a module can be assembled using compound micro-assembly techniques. For example, a glass wafer is provided with a patterned sacrificial layer and a substrate layer to form the substrate 62. The iLED 32, an integrated circuit incorporating the electronic circuit 40, and the acoustic wave filter 52 are each micro-transfer printed from individual different source wafers to the glass wafer (substrate 62). Using photolithographic techniques, electrically conductive wires 64 are patterned over the components and the glass wafer, for example by evaporating or sputtering an aluminum metallization layer and pattern-wise etching (using optically sensitive photoresist and optical masks) the metal layer to form the antenna 50 and wires 64. A dielectric is deposited, for example silicon dioxide using sputtering or evaporation, or by coating or laminating a layer of a dielectric material such as SU8. The process can be repeated multiple times to make a multi-layer antenna 50 with an increased number of turns. Electrical connections (wires 64) can be formed by etching vias and patterning deposited metal in the vias. A passivation layer can be provided for environmental protection. The substrate 62 and the components can have a thickness of only a few microns and the completed structure can have a thickness of less than 35 μm. The light-emitting modules 60 can be formed over a patterned sacrificial layer for micro-transfer printing. The patterned sacrificial layer is etched to form the tethers 34 and the micro-transfer printable light-emitting modules 60 (as in FIG. 3). A stamp is pressed against the light-emitting modules 60, fractures the tether 34, and transfers the light-emitting modules 60 to a destination substrate such as the ribbon 70 (step 140 of FIG. 7).

Referring to FIG. 19 in more detail, the light emitter 30 (e.g., an iLED), the acoustic wave filter 52, and the ASIC 66 can be formed in different materials for example AlN for the acoustic wave filter 52, a compound semiconductor such as GaAs or InGaN for the light emitter 30 (e.g., an iLED), and silicon for the ASIC 66. A source wafer (e.g., iLED source wafer 36) for each of these devices in a suitable material is formed in steps 300, 310, and 320, respectively. An intermediate substrate (e.g., substrate 62) is provided and the light emitters 30, the acoustic wave filter 52, and the ASIC 66 are each micro-transfer printed onto the substrate 62 in steps 330, 340, and 350, respectively, but can be transferred in any desired order. If any or all of the devices are micro-transfer printed, each will include a fractured tether 34 (FIG. 3). Alternatively, other transfer methods can be used. After the devices are all transferred to the substrate 62, electrical connections can be formed, for example using photolithographic methods to form electrical connections such as wires 64, in step 360, as well as the antenna 50.

Referring to FIGS. 20 and 21, in further embodiments of the present invention, the antenna 50 is a multi-layer antenna. Since the signal captured by the antenna 50 is partly dependent on the number of turns, or coils or windings, in the antenna 50, it can be useful to increase the number of such turns to increase the signal magnitude. In the simplified illustration of FIG. 20, multiple layers 51 of antenna turns are separated by dielectric layers 54 with each antenna layer 51 connected to an adjoining antenna layer 51, for example through a via (not shown). In an embodiment, adjoining antenna layers 51 are connected alternately near the edge and near the center of the antenna 50, thus reducing the number of layers and vias needed. In an embodiment, the number of layers 51 in the multi-layer antenna 50 is even, as shown in FIGS. 20 and 21 so that each end of the loop antenna 50 can be electrically connected to the electronic circuit 40, forming a loop antenna 50 or providing a relative ground for the electronic circuit 40. The electrical connections to the electronic circuit 40 from the antenna 50 can be at or near the center of the substrate 62, as shown. Thus, in an embodiment, the antenna layers 51 are alternately connected near the edge of the antenna 50 and near the center of the antenna 50, where the center of the antenna 50 is near the center of the spiral formed by the turns of the electrical conductor forming the antenna 50. Moreover, in an embodiment the antenna layer 51 farthest from the electronic circuit 40 is electrically connected to the electronic circuit layer nearer the center of the antenna layer 51 than the edge of the antenna layer 51. The dielectric layers 54 keep the various layers 51 of antenna turns from electrically shorting together or electrically shorting to the light emitters 30, the acoustic wave filter 52, the ASIC 66, or the wires 64 (collectively devices, the wires 64 are not shown in FIGS. 20, 21). The dielectric layers 54 can be formed by coating, embossing, and filling, e.g., with curable conductive ink, photolithographic deposition and patterning, or laminating subsequent layers of materials, for example a curable resin or other plastic layer and can encapsulate the electrical conductor making up the antenna 50. A laminated layer can include an antenna layer 51. The vias between and connecting layers 51 can be formed with photolithography or can be a part of the layer applied.

In the embodiment of FIG. 20, the devices are formed or disposed on the substrate 62 and the layers 51 of antenna turns are formed in the same layer and above the devices so that the electronic circuit 40 is located between the antenna portion and the banknote 20 and at least a portion of the antenna 50 is located on a side of the electronic circuit 40 opposite the banknote 20. In a particular embodiment, the devices are directly beneath (or above) one or more of the antenna turns, reducing the area of the light-emitting modules 60. The substrate 62 is then disposed on or adhered to the ribbon 70 in step 370, for example by micro-transfer printing, or by other means, so that the light emitters 30 emit light through the ribbon 70. In the embodiment of FIG. 21, the same process can be used to make the multi-layer antenna 50 and device structure, but the top antenna 50 layer is disposed or adhered to the ribbon 70, so that the light emitters 30 emit light in a direction opposite the ribbon 70. In this case, a portion of the antenna 50 is located between the integrated circuit 66 and the banknote 20 (ribbon 70). In step 380, the ribbon 70 is incorporated into a banknote 20.

A plurality of substrates 62 can each be provided and the light-emitting module 60 made individually on each substrate 62. In a more efficient process, the substrate 62 is originally much larger than the light-emitting module 60 and multiple light-emitting modules 60 are formed on a common substrate 62 at the same time using the same process steps, such as micro-transfer printing, photolithographic steps, and coating. The substrate 62 can then be diced, for example by scribing and breaking, diamond saw cutting, or laser cutting, to form the individual light-emitting modules 60, such as surface-mount devices. However, it is an advantage of the present invention that very small light-emitting modules 60 can be formed so that conventional methods of separating individual light-emitting modules 60 or disposing light-emitting modules 60 onto a ribbon 70 can be difficult. Therefore, in an embodiment of the present invention, the light-emitting modules 60 are micro-transfer printable light-emitting modules 60 formed over sacrificial portions of a sacrificial layer and fastened with tethers 34 to anchors on the substrate 62. The individual light-emitting modules 60 are then disposed on the ribbons 70 using micro-transfer printing stamps to contact the light-emitting modules 60, the tethers 34 are fractured, the light-emitting modules 60 are transferred to the ribbon 70, the light-emitting modules 60 are applied to the ribbon 70 to adhere them to the ribbon 70 (for example on an adhesive layer on the ribbon 70), and the stamp is removed.

In the case in which the substrates 62 are diced to provide individual light-emitting modules 60, the devices can be disposed on the substrates 62 using micro-transfer printing. In this case, to reduce the number of print steps, it is useful to provide a substrate 62 whose size is on the order of the source wafer 36 size so that many devices from each source wafer 36 can be transferred in a single stamp transfer step. However, in an embodiment in which the light-emitting modules 60 are also micro-transfer printed (rather than just the devices from the source substrate 36), it is useful to provide a substrate 62 whose size is on the order of a web of ribbons 70 that are destination substrates for the micro-transfer process. For example, if the ribbons 70 are 2 mm in width and it is desired to micro-transfer print five hundred light-emitting modules 60 at a time, a web of ribbons 70 can be one meter in width and the substrate 62 can be a similar size, thereby reducing the number of micro-transfer printing steps necessary to dispose a light-emitting module 60 on each ribbon 70.

In other embodiments of the present invention, one or more light emitters 30, an integrated circuit 66 or, optionally, an acoustic wave filter 52 are micro-transfer printed onto a substrate 62 to form a light-emitting module 60 and the light-emitting modules 60 incorporate the substrate 62. In a further embodiment, a plurality of the one or more light emitters 30, integrated circuits 66 or optional acoustic wave filters 52 are micro-transfer printed onto the substrate 62 to form light-emitting modules 60. The light-emitting modules 60 are, in turn, micro-transfer printed onto the banknote 20 or onto a flexible substrate, film, thread, or ribbon 70 subsequently incorporated in, laminated to, or woven into the banknote 20. A plurality of the light-emitting modules 60 can be micro-transfer printed from the substrate 62 onto a plurality of the banknotes 20 or onto one or more of flexible substrates (e.g., ribbon 70) in a single step, for example in a web and a roll-to-roll process. In an embodiment, the substrate 62 has an area or dimension that is equal to or larger than a corresponding area or dimension of the documents 20, e.g., banknotes 20 or flexible substrates, e.g. ribbons 70. For example, if the ribbons 70 or banknotes 20 are provided in a web, the substrate 62 can have a width or length dimension that is at least as large as the width of the web. The substrate 62 can have an extent (for example an x or y dimension, length or width, but not a thickness or z dimension) or area that is within a range of one tenth to ten times an extent or area of the flexible substrate (for example a width of a web), within a range of one quarter to four times an extent or area of the flexible substrate, within a range of one half to two times an extent or area of the flexible substrate, or within 25%, 10%, or 5% of an extent or area of the flexible substrate. By providing a substrate 62 having a size that is the same order of magnitude, comparable, or larger than the destination substrate of the micro-transfer printing step, the number of separate print steps can be reduced since each print step can transfer more light-emitting modules 60.

Referring to FIG. 13, in an embodiment of the present invention, a hybrid banknote 10 according to the structure of FIG. 12 can be constructed by first providing a roll of polyimide film (1302). The light-emitting modules 60 are micro-transfer printed onto separated portions of the polyimide layer (1304), which acts as the ribbon 70. Alternatively, the different components of the light-emitting module 60 are micro-transfer printed onto the roll of polyimide film itself and processed photolithographically to complete the light-emitting modules 60 so that the polyimide film serves as the substrate 62 (not shown) and can be a common substrate for multiple light-emitting modules 60. The roll of polyimide file is sprayed with a protective layer (1306) and a thermoset adhesive layer (1308) and slit into strips (1310). Each strip is then cut into portions suitable for each banknote 20, applied to the banknote 20, and heated to complete the hybrid banknote 10 (1312).

In the present invention, it is important that the antenna 50 provide sufficient power to the electronic circuit 40 to cause the light emitter 30 to emit light. FIG. 14 is a table presenting various design choices to enable a corresponding variety of functional embodiments of the present invention. Table 14 provides example antenna 50 dimensions based on the power required by an iLED 32 load. As shown, small antennas 50 suitable for small light-emitting modules 60 generate small output voltages that can be increased using acoustic wave filters 52 operating in a resonance condition. An increased voltage of 0.5 V is sufficient to be converted with a charge pump in the electronic circuit 40 to drive an iLED 32 at 0.3 μA at 3.3 V.

The light-emitting module 60 structure of the present invention disposed on the banknote 20 can be generally employed in multi-element light-emitting systems. For example, in an embodiment of the present invention, a multi-element light-emitting system comprises a plurality of independent light-emitting modules 60, each independent light-emitting module 60 including an antenna 50 with multiple turns, an electronic circuit 40, and a light emitter 30 mounted and electrically connected on a separate substrate 62. The independent light-emitting modules 60 are disposed in a pattern to form a visible indicator and can be disposed on a variety of underlying structures including, but not limited to, banknotes 20.

The light-emitting modules 60 of the present invention emit light when the light-emitting modules 60 are located in an NFC magnetic field. Referring to FIG. 15, such a field can be provided by a hybrid banknote mat 80, comprising a mat circuit 84 and an antenna 50 (not shown but similar to those found in existing NFC terminals or smart phones, e.g., FIG. 9B). Although illustrated as a largely planar mat, the form factor of the mat 80 is not limited to any specific form factor and can be similar in structure to any NFC reader/writer. The mat circuit 84 provides a continuous or pulsed NFC signal, the pulsed NFC signal having a pulse rate of ten, twenty, fifty, or one hundred pulses per second or greater. This pulse rate is much higher than those found in conventional NFC terminals or smart phones so that the light-emitting modules 60 of the present invention will emit light at a sufficient frequency as to be visible to the human eye. As illustrated in FIG. 16, the NFC field can operate for 2 msec out of every 20 msec and a 50 Hz frequency. Each such NFC circuit can drive thousands of light-emitting modules 60 to emit light, enabling a wide variety of patterns, applications, and effects. The mat 80 can include a display 82 responsive to the mat circuit 84. The hybrid banknote 10 of the present invention can also be interacted with by conventional NFC devices.

In a further embodiment of the present invention, the electronic circuit 40 stores information in the memory 44, for example serial number information, value information, manufacturing information, usage information, or location information. This information can be retrieved using RFID or NFC techniques and read, for example by the mat 80 and the information, or an aggregation of the information, displayed on the mat 80 with the the display 82. For example, the mat display 82 can display the sum of the values of the hybrid banknotes 10 located on or very near the mat 80. The mat 80 can also include switches, buttons, or other user-interactive devices for controlling the mat 80 to perform various desired functions or select options. For example, options can include displaying value, serial number, or manufacturing date, location of the hybrid banknote 10. Information can be encrypted, can be changed (if the memory 44 includes writable or rewritable memory). Thus, in an embodiment, a device, for example the mat 80, can write information into the electronic circuit. The information can also be communicated to and stored in an information registry independent of the hybrid high-security document 10 or banknote 20. If the information is a value, the banknote 20 can then have the stored value rather than a denomination printed on the banknote 20.

The mat 80 can be a part of a cash register or management system and can detect the value and serial identification of the hybrid banknotes 10 in the system to provide a currency inventory. Such a cash register system can provide security and theft detection. Hybrid banknotes 10 that have missing or non-functional light-emitting modules 60 can be detected by comparing the number of detected light-emitting modules 60 to the expected number of light-emitting modules 60. A hybrid banknote 10 can even be deactivated or the light-emitting modules 60 can be placed in a deactivated state.

In further embodiment of the present invention and as illustrated in FIG. 17, a method of using a hybrid banknote 10 comprises the steps of providing a hybrid banknote 10 in step 200, exposing the hybrid banknote 10 to an electromagnetic field so that the antenna 50 provides power to the electronic circuit 40 and causes the light emitter 30 to emit light in step 210, and observing or detecting the light in step 220. In an alternative embodiment and as shown in FIG. 18, the electromagnetic field is provided by the mat 80 in step 215, the electronic circuit 40 stores information, for example in the memory 44, the information is read from the hybrid banknote 10 in step 217, and the display 82 is responsive to the information. Alternatively, the information from the hybrid banknote 10 is transferred to a computer system for action or processing in step 230. Information can also be written into a hybrid banknote 10.

The electronic circuit 40 can also be an integrated circuit, for example a small chiplet, suitable for micro-transfer printing. The electronic circuit 40 can include digital circuits or logic (for example CMOS circuits) and power circuits (for example for driving an LED). The electronic circuit 40 can include information storage circuits, a state machine, or a stored program machine to implement the desired functionality of the hybrid banknote 10. The electronic circuit 40 can read or write information such as currency values, process information, respond to input and provide output.

In a further embodiment, the iLEDs 32 and electronic circuit 40 are too small to be readily visible with the unaided human eye. Furthermore, the iLEDs 32 and electronic circuit 40 can be located in areas of the banknote 20 that include visible markings 22 to further obscure the presence of the iLEDs 32 and electronic circuit 40, as well as any wires 64. In one embodiment, any of the iLEDs 32, electronic circuit 40, or wires 64 are marked with visible markings 22. For example, ink can be printed over the non-emitting side of the iLEDs 32, electronic circuit 40, or wires 64 to obscure them or otherwise make them a part of the visible markings 22 on the banknote 20. Since the iLEDs 32, electronic circuit 40, or wires 64 can each be very small, for example having a size in the micron range, they can be effectively invisible to the unaided human eye. For example, the one or more inorganic micro light-emitting diodes 32 or the electronic circuit 40 of the hybrid banknote 10 can have a width from 2 to 5 μm, 5 to 10 μm, 10 to 20 μm, or 20 to 50 μm, a length from 2 to 5 μm, 5 to 10 μm, 10 to 20 μm, or 20 to 50 μm, or a height from 2 to 5 μm, 4 to 10 μm, 10 to 20 μm, or 20 to 50 μm.

In another embodiment of the present invention, the hybrid banknote 10 includes visible markings 22 that do not include a value. Such a hybrid banknote 10 can be a non-denominational banknote 20 that either has an assigned value or a variable value stored in a memory 44 in the electronic circuit 40. The memory 44 can be a read-only memory that encodes a desired assigned value. The assigned value can be a currency value or can include an electronic serial number, or both.

In the case in which the assigned value is variable, the memory 44 can be a write-once memory 44 that stores multiple values in memory locations that are ordered in a sequential order, for example by memory address. The write-once memory 44 can, for example, employ fuses that are electrically destroyed and cannot be rewritten. Alternatively, the memory 44 can be a non-volatile read-write memory. In this case, the value stored by the hybrid banknote 10 can change over time. The current value can be modified by, for example, a teller machine. If a change in the current value of the hybrid banknote 10 is desired, an input value can be input by a user with an input device. A teller machine controller can then calculate or otherwise determine a new stored value responsive to the input value and store the new value in the hybrid banknote 10, for example by communicating the new stored value to the electronic circuit 40 which then writes the new stored value in the memory 44. In an embodiment, the electronic circuit 40 only writes new stored values in the memory 44 that are smaller than the current value. In another embodiment, the electronic circuit 40 can write new stored values in the memory 44 that are larger than the current value, or that are larger than the current value but are limited to a maximum value. The change in current value of the hybrid banknote 10 can represent or be the result of a financial transaction, for example a purchase or a financial exchange with or facilitated by a financial institution such as a bank or government institution such as a central bank. Read-only memories, write-once memories, and read/write memories together with controllers and read/write circuitry can be formed in integrated circuits and electrical circuits. Devices for currency handling, optical inspection, displays, input devices (such as keyboards or touch screens) can be made using electromechanical, electronic, and optical technologies.

An assigned or current value can be programmed into the electronic circuit 40 or an associated memory 44 (also micro-transfer printed if it is a separate integrated circuit or chiplet) either before or after the electronic circuit 40 or memory 44 is micro-transfer printed. Alternatively, an external device such as a hybrid banknote teller machine (that can be a part of or include, for example, a mat 80) can communicate with the electronic circuit 40 to write an assigned or current value to the hybrid banknote 10. A hybrid banknote 10 teller machine can also communicate with a central or remote database to establish the legitimacy of the hybrid banknote 10, track its use or location, or approve a transaction and record or approve the transaction. The communication can include an electronic serial number.

U.S. patent application Ser. No. 14/743,981, filed Jun. 18, 2015, entitled Micro Assembled Micro LED Displays and Lighting Elements, incorporated herein by reference describes micro-transfer printing structures and processes useful with the present invention. For a discussion of micro-transfer printing techniques see also U.S. Pat. Nos. 8,722,458, 7,622,367 and 8,506,867, each of which is hereby incorporated by reference in its entirety. Micro-transfer printing using compound micro assembly structures and methods can also be used with the present invention, for example, as described in U.S. patent application Ser. No. 14/822,868, filed Aug. 10, 2015, entitled Compound Micro-Assembly Strategies and Devices, which is hereby incorporated by reference in its entirety.

As is understood by those skilled in the art, the terms “over”, “under”, “above”, “below”, “beneath”, and “on” are relative terms and can be interchanged in reference to different orientations of the layers, elements, and substrates included in the present invention. For example, a first layer on a second layer, in some embodiments means a first layer directly on and in contact with a second layer. In other embodiments, a first layer on a second layer can include another layer there between.

Having described certain embodiments, it will now become apparent to one of skill in the art that other embodiments incorporating the concepts of the disclosure may be used. Therefore, the invention should not be limited to the described embodiments, but rather should be limited only by the spirit and scope of the following claims.

Throughout the description, where apparatus and systems are described as having, including, or comprising specific components, or where processes and methods are described as having, including, or comprising specific steps, it is contemplated that, additionally, there are apparatus, and systems of the disclosed technology that consist essentially of, or consist of, the recited components, and that there are processes and methods according to the disclosed technology that consist essentially of, or consist of, the recited processing steps.

It should be understood that the order of steps or order for performing certain action is immaterial so long as the disclosed technology remains operable. Moreover, two or more steps or actions in some circumstances can be conducted simultaneously. The invention has been described in detail with particular reference to certain embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention.

PARTS LIST

-   10 hybrid banknote/hybrid high-security document -   20 banknote/document/high-security document -   22 visible markings -   30 light emitter -   32 inorganic light-emitting diode -   34 tether -   36 iLED source wafer -   40 electronic circuit -   44 memory -   50 antenna -   51 antenna layer -   52 power converter/acoustic wave filter -   54 dielectric layer -   60 light-emitting module -   62 substrate -   64 wires -   66 ASIC -   70 ribbon -   80 mat -   82 display -   84 mat circuit -   100 provide banknote with markings step -   110 provide module wafer step -   120 micro-transfer print modules on banknote step -   130 provide ribbon step -   140 micro-transfer print modules on ribbon step -   150 integrate ribbon in banknote step -   200 provide hybrid banknote step -   210 expose hybrid banknote to NFC field step -   215 expose hybrid banknote to NFC field from mat step -   217 read information from banknote step -   220 observe/detect emitted light step -   225 observe display step -   230 transfer information to computer system step -   300 provide iLED source wafer step -   310 provide SAW source wafer step -   320 provide ASIC source wafer step -   330 micro-transfer print iLED to intermediate substrate step -   340 micro-transfer print SAW to intermediate substrate step -   350 micro-transfer print ASIC to intermediate substrate step -   360 form interconnections and antennas step -   370 micro-transfer print modules to ribbon step -   380 integrate ribbons into banknote step 

What is claimed:
 1. A hybrid high-security document, comprising: a flexible document; and a plurality of independent light-emitting modules disposed on or embedded in the flexible document, each module comprising: an antenna with multiple turns, an electronic circuit, and a light emitter mounted and electrically connected on a substrate separate from the flexible document, wherein the electronic circuit is responsive to electrical power provided from the antenna to control the light emitter to emit light, wherein the electronic circuit is formed in semiconductor that has an area less than fifty thousand square microns, wherein (i) the plurality of light-emitting modules is spatially disposed to collectively form at least one of a character, a graphic indicator, an icon, a number, a letter, and a pictogram, (ii) the plurality of light-emitting modules is spatially disposed to collectively indicate a value, a date, or a person, or (iii) both (i) and (ii).
 2. The hybrid high-security document of claim 1, wherein the light-emitting module has an area less than one hundred thousand square microns.
 3. The hybrid high-security document of claim 1, comprising a flexible substrate, ribbon, film, or thread incorporated in, laminated to, or woven into the flexible document and wherein the one or more independent light-emitting modules are mounted on, embedded in, or micro-transfer printed onto the flexible substrate, ribbon, film, or thread.
 4. The hybrid high-security document of claim 3, wherein the flexible substrate, ribbon, film, or thread comprises paper, plastic, impregnated paper, or metal foil.
 5. The hybrid high-security document of claim 3, wherein the flexible substrate, ribbon, film, or thread is electrically insulating.
 6. The hybrid high-security document of claim 1, wherein the light-emitting modules of the plurality of light-emitting modules are electrically independent and electrically disconnected.
 7. The hybrid high-security document of claim 1, wherein the flexible document has visible markings and the one or more light-emitting modules are disposed in a location corresponding to a portion of the visible markings to highlight or otherwise indicate or emphasize the portion of the visible markings.
 8. The hybrid high-security document of claim 1, wherein the electronic circuit controls the light emitter within a light-emitting module to flash once or to flash sequentially.
 9. The hybrid high-security document of claim 1, wherein the one or more light-emitting modules include inorganic light-emitting diodes that emit different colors of light.
 10. The hybrid high-security document of claim 9, wherein the different colors of light include red, green, and blue.
 11. The hybrid high-security document of claim 1, wherein the antenna is a multi-layer antenna formed in multiple layers.
 12. The hybrid high-security document of claim 11, wherein the electronic circuit is in a layer and the antenna layer farthest from the electronic circuit is electrically connected to the electronic circuit layer nearer to the center of the electronic circuit layer than to the edge of the electronic circuit layer.
 13. The hybrid high-security document of claim 1, wherein the electronic circuit and light emitter are powered solely by the energy received from the antenna.
 14. A hybrid high-security document mat, comprising: a mat circuit; and an antenna, wherein the mat circuit generates a continuous or pulsed NFC signal, the pulsed NFC signal having a pulse rate of ten, twenty, fifty, or one hundred pulses per second or greater.
 15. The hybrid high-security document mat of claim 14, comprising a display responsive to the mat circuit.
 16. A multi-element light-emitting system, comprising: a plurality of independent light-emitting modules, each independent light-emitting module comprising: an antenna with multiple turns, an electronic circuit, and a light emitter mounted and electrically connected on a separate substrate, the light emitters of the independent light-emitting modules spatially disposed in a pattern to form a visible indicator, wherein the electronic circuit is formed in semiconductor that has an area less than fifty thousand square microns. 